GALLIA CISALPINA, that portion of northern Italy north of Liguria and Umbria and south of the Alps which was inhabited by various Celtic and other peoples, of whom the Celts were in continual hostility to Rome and rendered assistance to Hannibal. In early times it was bounded on the south by Liguria and the Aesis; Sulla readjusted the boundaries and in Caesar's time the south-east boundary was the Rubicon. (See Mommsen, Hist. of Rome, Eng. trans., bk. iv. c. io.) For the early Celtic and other peoples and the later history of the district see ITALY : Ancient, and ROME : History, Ancient.